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Grout or leveling glue? Epoxy under lathe feet?

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  • Grout or leveling glue? Epoxy under lathe feet?

    Grout or leveling glue? Epoxy under lathe feet?

    There was a hard dry layer of plaster of paris looking product between the top of my lathe cabinet and the underside of the lathe foot riser block.

    I know it needs some sealant to stop coolant leaking underneath the riser blocks.

    Are you also supposed to use some kind of product that sets harder so that you can make a better surface to surface contact area?

  • #2
    It certainly has been done with epoxy, but grout works fine. Ultimately I don't think it matters as long as you have a lot of contact area and get the lathe as level as possible. You could always go around the bottoms of the feet with some tub and tile caulk after it all sets up. BTW, welcome to HSM!


    • #3
      If you simply bolt everything down with some manner of sealant then I'm rather thinking that the bed of the lathe will be twisted or not as per the condition of the cabinet. Granted it's a very solid and stiff looking cabinet. But if there is any twist then it would be that much more locked in.

      With that in mind I think I'd approach it as follows;
      • Clean up and ensure that the pedestals seat well on the base areas of the bed. Scrape or otherwise treat to ensure a large supportive contact area. If that means bedding the parts with epoxy then I'd use a filled epoxy such as JB Weld or Hysol rather than simple regular epoxy.
      • Seat the cabinet on the floor and adjust what should be adjustable feet to sit solidly and evenly on all four feet. Mark the floor so if you ever have to move the lathe for any reason you can put it back in the same spot give or take as little as a quarter inch.
      • For the joints between the pedestals and the chip tray I'd be inclined to just bolt it down and then do the usual test for bed twist as so often described around here and other places online. If you are good for lack of twist and lack of arching or swayback in the bed then great. If not start shimming between the pedestals and chip tray as required. Do all this "dry".
      • Once shimmed as needed and the machine is true in all ways while bolted down to a specific known torque lift the lathe off far enough to add a suitable bead of gasket sealant around the edges and let the lathe settle back down and torque the bolts to the known amount.
      At that point it should be good in all respects to go ahead with the rest of the assembly. And if you are going to use water containing cutting fluid I think I'd be inclined to use some liquid gasket goop when you put the headstock in place to keep any water bearing fluid from getting between the head stock and bed ways. I find that a lot of such fluids if they cannot evaporate easily end up rusting the iron. Sealant in that joint should avoid that risk.
      Chilliwack BC, Canada


      • #4
        Infundibular cement, it will adjust itself to the lathe bed over time, however you may not live that long.

        Barring that just bolt it down a have at it (-:


        • #5

          Yeah I just quickly put the feet into rough position and there is a fair bit of a gap around the edges of the feet here and there. The reason being is that the top of the cabinet is welded underneath. The welds have pulled the top down and that is why there is a gap. So I do not think that there is actually that much contact area there at all. So I guess that I just bolt all the surfaces together and put JB Weld or Hysol in between to fill up all the air gaps.

          But then if I do that how can I shim up the feet If I need to true it all up? Maybe I need to do what I said just now. But when I need to shim, I can maybe shim the joint at the top of the riser instead of the bottom of the riser?


          • #6
            Lots of people shim it up and grout the shims right in along with everything else. For example get it set with shims, put your epoxy or whatever, and set it right on top of that. It'll all squeeze out to what it needs to be, and harden up. Wait a few days then tighten the bolts up.


            • #7
              You got my suggestion for JB or Hysol but I'm guessing that the step where I suggested shimming didn't make sense for some reason? My apologies if that part was not clear enough.

              But yeah, what I posted earlier and what NCF says above. You attach the pedestals to the bed first. And any shimming is done between the pedestals and the chip tray. And you would not epoxy or otherwise bed anything at this point anyway. Shimming and final sealing would be later after the lathe is fully assembled and being tested for trueness.

              Looking at the picture in your first post I'm pretty sure I see paint on the top of the pedestals where the bed will be seated. So first step before anything is to scrape that paint off carefully. Do not sand it off as that will remove some metal. Scrape it off with care to remove only the paint. And if this is new paint and you painted the underside of the bed where the pedestals fit then scrape those clean too. No paint between any joints! ! ! At most you would only apply a small string like bead of gasket goop or sealant to keep water based coolants out of the joint and avoid it causing long term rusting. Any paint and then epoxy in there will act like unwanted shims because the chance of it being consistent thickness is slim to nil. When you remove the paint the pedestals will likely fit very nicely to the seats intended on the bottom of the bed.

              The chip tray in the first post picture appears to be sheet metal. If so it is likely warped a bit. Sheet metal loves to warp like that. Lift it off and set the bed and pedestals down onto the top of the main cabinet. How do the bases of the pedestals fit now? If things true up pretty well then when you tighten the hold down bolts the chip tray will be pulled down just fine.

              At any rate it is certainly not time to use any epoxy or anything else in those joints. Especially not to make up for a poor fit caused by any paint that should be removed first. And the whole lathe needs to be assembled and set in place and provided the cabinet under the chip tray is pretty true the whole assembled lathe needs to be bolted down and only then tested for true. And shimmed from that point as needed. The shims should be made so that when fitted that the outer edges are back in from the outer edge of the pedestal feet. That way when you do the final lift to allow placing a bead of sealant (NOT EPOXY) around the outer edge of the pedestal and set it back down for the final torqueing you get a good seal. At that point you double check the trueness of the bed with a final test skim and measuring on the test bar and if needed tweak the bolt torques for that last little bit.
              Last edited by BCRider; 02-11-2020, 01:56 PM.
              Chilliwack BC, Canada


              • #8
                I have a couple lathes, some new some old. Ive never thought about how square it was to Earth. Over thinking it,

                I dont see a need too level out the property for a Lathe or Mill.. It really is a nice shop though. JR
                My old yahoo group. Bridgeport Mill Group